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Finding the Third Proportional to 391.50 and 840.38

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Solution

The third proportional to 391.50 and 840.38 is: 1,803.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.50 : 840.38 = 840.38 : x
  2. Step 2: Convert to fraction form
    391.50/840.38 = 840.38/x
  3. Step 3: Cross multiply
    391.50x = 840.38 × 840.38
  4. Step 4: Simplify right side
    391.50x = 706,230.14
  5. Step 5: Solve for x
    x = 706,230.14/391.50
  6. Step 6: Final answer
    x = 1,803.91

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Why These Related Problems?

These problems maintain the same ratio (2.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.